Precedence issues with mathematica functions

[sagetrac-flawrence]

Pre #9032:

sage: mathematica(pi/2).N(50)
1.5707963267948966192313216916397514420985846996876

Post #9032:

sage: mathematica(pi/2).N(50)
1.5707963267949

The N[] function from mathematica is being overwritten by numerical_approx. There seems to be no other way to call N[] on an existing mathematica object, so this is a problem.

One way to solve this would be to make mathematica functions take precedence over all or most Sage methods. To call a Sage method one would/should/could use .sage().whichever_method()

CC: @sagetrac-drkirkby

Component: interfaces: optional

Issue created by migration from https://trac.sagemath.org/ticket/10968